Why it's so hard for Toyota to find out what's wrong with its vehicles
I won’t lie to you: I was not a good engineering student. That’s one of the reasons I went into journalism. But I did manage to acquire a bachelor of sciences in mechanical engineering, and the recent Toyota hearings on Capitol Hill brought back a lot of memories. Specifically, memories about how engineers figure out why mechanical things fail.
It was made painfully clear at the hearings that a number of lawmakers do not understand the process. An exchange between Rep. Eleanor Holmes Norton (D-D.C.) and Toyota president Akio Toyoda illustrated the problem.
Toyoda said that when his company gets a complaint about a mechanical problem, engineers try to duplicate the problem in their labs as a way of trying to find out what went wrong. Norton said: “Your answer — we’ll wait to see if this is duplicated — is very troublesome.”
Norton asked Toyoda why his company waited until a problem happens again to try to diagnose it, which is exactly what he was not saying.
Members of Congress are lawyers and politicians, not engineers. But they are launching investigations and creating policies that have direct impact on the designers and builders of incredibly complex vehicles — there are 20,000 parts in a modern car — so there are some basics they should understand. Chief among them: The only way you can credibly figure out why something fails is to attempt to duplicate the failure under observable conditions. This is the engineering method.
“It’s just so difficult for people to understand the complexity of the thing,” said David E. Cole, chairman of the Center for Automotive Research and an engineer. “They don’t have the background. They don’t have the time to do an investigation. They want to oversimplify a thing that can’t be oversimplified.”
Toyota is facing an incredibly difficult task. Here’s what it knows: It has received hundreds of complaints of unintended acceleration in its vehicles over the past several years. People have died in these crashes. Over the same period of time, hundreds more people have died in Toyota crashes that had nothing to do with runaway acceleration. After that, it knows nothing.
Toyota must search its data and look for patterns, for similarities among the incidents. It must consider the kinds of road conditions where they happened (Is it a rain/snow/sleet/temperature problem?), where the cars were made (Is it a parts or assembly problem?), how the cars were drawn up (Is it a design flaw? If so, is it a mechanical or electronic flaw? Or a combination?), how the cars were tested (Did we fail to anticipate a series of events that would lead to a flaw?), it if is a fatigue problem (Did something break down sooner than we thought it would?) and a dozen other variables I’m not thinking of.
Then you go through a process of elimination. It’s not dissimilar to a doctor diagnosing an illness: You take a thorough reading of the symptoms then start eliminating causes. You treat what you think is the illness. If it doesn’t go away, you treat your second guess at the illness.
Toyota appears from the start to have removed its electronic throttle control from the list of possible causes of the runaway acceleration and focused on two mechanical issues: floor-mat entrapment and sticky gas pedals.
But the National Highway Traffic Safety Administration is expanding its search for the problem. It purchased a 2006 Lexus that experienced runaway acceleration and will test it for everything it can think of — including electronic problems. I asked NHTSA about the Lexus testing, which will take place at the agency’s facility in East Liberty, Ohio, but no details were available yet.
So I called Prof. Giorgio Rizzoni of Ohio State University, an expert in failure analysis and director of the school’s Center for Automotive Research. I asked him: How will NHTSA test its Lexus?
First, he said, the vehicle will be outfitted with instruments and taken to a proving ground. There it will be driven for hours by a test-driver to see if the runaway acceleration can be duplicated.
“But what if you keep driving for days and days and the fault doesn’t come back,” Rizzoni said. “What do you do at that point?”
Then, the car is taken into a lab and taken apart.
If the electronic throttle control is the suspected culprit, it is removed from the Lexus and set up on a test bench, where it is affixed with monitoring equipment and a power source. You give it juice and see what happens; see if there are drops or surges in micro-voltage that could lead to runaway acceleration, for instance.
If that doesn’t provide the answer, you go 21st-century on the thing. You run something called a “hardware-in-the-loop simulation,” where you hook up the physical throttle assembly to a virtual Lexus, via a complex computer. This lets you test the throttle control up-close while it is subjected to road conditions, via the computer simulation. You can run tests for days on end without the expense of a test-driver.
Though attention has been focused on mechanical and electronic issues, Rizzoni raised another possible cause of the runaway acceleration: a software glitch.
He explained that each vehicle on the road today contains “layers of computer code that may be added from one model year to next” that control nearly every system of a vehicle, from acceleration to braking to stability. Rizzoni said this software is rigorously tested before it is put into vehicles, but added: “It is well-known in our community that there is no scientific, firm way of actually, completely verifying and validating software.”
Here’s an example everyone is familiar with: You’re working at your computer in Windows software and an error message pops up. It asks if you want to report the error to Microsoft. Microsoft has exhaustively tested this version of Windows before its release, but it cannot completely predict how it will operate in the wild, subject to user demands. That’s why it gathers error reports and uses them to fix the software on a rolling basis.
If you put a lot of parts together to form a complex electro-mechanical machine and make it talk to itself via software, it can behave, sometimes, in ways you cannot anticipate. It can fail for reasons you cannot anticipate.
That’s the problem Toyota faces. And. after thorough testing by Toyota, and NHTSA and garage mechanics trying to win the $1 million Edmunds.com prize, no single answer may be found. Obviously, this will not stop juries from awarding damages in the liability lawsuits already filed.
Finally, Toyota can’t say this, but I can: Some of the cases of runaway acceleration could have been caused by driver error. Think about the times you’ve been in an accident, a near-miss or — more to the point — a distracted-driving situation that almost got out of control. You remember the white-hot spike of fear that shot up your spine. You remember the shakes afterward. But do you remember what you did during those few seconds of panic? Do you remember where your feet and hands and eyes went?
Quoting from a 2009 Los Angeles Times story on runaway Toyota acceleration:
Richard Schmidt, a former UCLA psychology professor and now an auto industry consultant specializing in human motor skills, said the problem almost always lies with drivers who step on the wrong pedal.
"When the driver says they have their foot on the brake, they are just plain wrong,’ Schmidt said. ‘The human motor system is not perfect, and it doesn’t always do what it is told.”
If you were lucky, your reflexes and muscle-memory and driving experience — and sheer chance — saved you and you emerged unscathed from your near-miss. But you could just have easily smashed your foot down on the wrong pedal or jerked the wheel the wrong way. Or hit the radio volume and scared yourself into a dangerous maneuver. Or made a dozen other mistakes. And none of those would have been the fault of the automaker.
Follow me on Twitter at @theticker
March 4, 2010; 1:31 PM ET
Categories: Congress , Corporations , The Ticker | Tags: Akio Toyoda, David Cole, Eleanor Holmes Norton, Toyota problems, Yoshimi Inaba, auto engineering, automotive engineering, engineering testing, testing toyota software, toyota, toyota congressional hearings
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